and somewhere in the specs there is a minimum weight rating per wheel but unfortunately I don't know where to find this.

R

edit: at least I found something:
the weight rating per wheel is expressed in the Load Index of the tyres
so for the fronts: 99 means 750 kg, for the rears 102 means 850 kg and Y is the max Speed index of the tyre (Y = up to 300 Km/h)